The lifespan of a retainer depends on how well you take care of the retainer, as well as how well you take care of your mouth. Potentially, retainers can last for years if routinely cleaned and if you avoid damaging them. On average, removable retainers can last for about 5-10 years, while permanent retainers can last for decades. To maintain the straight smile your Orthodontic treatment helped you achieve, you will need to wear a retainer nightly for the rest of your life. However, it is important to note that after some time it will not be necessary to wear them as often.